[Bug driver/115990] Consider deprecating -Ofast

[aaron at aaronballman dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=115990

--- Comment #3 from Aaron Ballman <aaron at aaronballman dot com> ---
(In reply to Andrew Pinski from comment #1)
> I don't think it should be deprecated or removed. It still has its uses.

Can you explain what those uses are and why they're not served by a more
explicit command line with `-O3 -ffast-math`? Mostly trying to understand if
there's something we've missed with Clang's assessment.

> Documentation is clear too.
> 
> We just fixed some documentation about the flags being enabled by -Ofast too.
> 
> People will never read the documentation either way anyways.

Agreed, that's part of why we're deprecating.